Sensors, in particular angle sensors determine an actual position of a component to be monitored, e.g. an angle position and emit this in the form of an electrical signal for further processing.
In magnetic field sensitive sensors a sensor element typically includes an integrated electronic circuit in the form of a chip which can measure the pole orientation of a magnetic field, wherein the sensor element is disposed within an area influenced by the magnetic field.
Accordingly, the sensor element is disposed in a tight housing from which only a cable is run out for putting out signals, whereas a magnet configured as an encoder element is arranged on a component to be detected, e.g. a rotating shaft outside of the housing and opposite to the sensor element.
Since applications of this type often take place under rough environmental conditions like high pressure, high temperature, and aggressive chemicals or similar, the service life of a sensor typically does not depend from the service life of the actual sensor element, but the service life depends from the amount of time during which the housing surrounding the sensor element remains tight. As soon as the housing develops a leak, humidity penetrates towards the sensor element and causes erroneous measurements, short circuits or a destruction of the sensor element or of its connections.
For this reason, it was attempted in the past in various ways to keep the housing surrounding the sensor element tight over a time period that was as long as possible. Thus, typical sealing measures like e.g. threading two housing components together through a seal inserted there between, e.g. an O-ring were attempted like also non-disengagable sealing of a housing in that two housing components e.g. housings and covers were glued together.
However, glue joints can also disengage again depending on the prevailing temperature and depending on chemical properties of surrounding media.
Besides that attempts were also made to keep the number of contact points of the housing to be sealed as low as possible.
Additional measures were encasing the sensor element with a hardening encasement compound in simple cases instead of a surrounding stable housing, typically, however, the encasement was performed in addition to the stable housing in the interior of the housing.